After speculation when American Samoa would also join NANP, +1 684
(NPA/area code 684) became a reserved area code.
A formal migration plan from +684 to +1 684 was approved by March 2003.

Migration timeline:

April 2001: United States and American Samoa territorial governments,
in conjunction with the primary telecom carrier makes a "formal" application
to the ATIS-INC and
NANPA and
FCC, to officially join the NANP.
Various US Federal Government agencies have reportedly wanted this
for several years.

24 December 2002: United States regulator Federal Communications Commission
approves plan to include American Samoa in the
NANP (country code +1).

2 October 2004: permissive dialling of +1 684 begins (+684 country code
may still be used until mandatory dialling commences). Also, American Samoa
carriers may request "Central office" or exchange codes from
NANPA (that is, the three digits past
+1 684, or first three digits of 7-digit subscriber number).

2 April 2005: mandatory dialling commences - calls to American Samoa must
be made using +1 684 (North American Numbering Plan). Attempts to use
country code +684 will obtain a recorded message. Also, the test number
established for 2 September 2004 is expected to be discontinued.
Country code +684 becomes an available code for ITU assignment.

2 April 2007: recorded message advising of discontinued +684 country
code is to remain available until this date.

American Samoa number ranges as of 3 Mar 2003, with +684
changed to +1 684 for the following number ranges: